Update IANA timezone db to 2018g

According to the announcement at
  https://mm.icann.org/pipermail/tz-announce/2018-October/000052.html ,

Morocco switches from +00/+01 to permanent +01 effective 2018-10-27,
so its clocks will not fall back on 2018-10-28 as previously

The tz-related files are updated by running update_tz.sh and ICU
data files are rebuilt.

In 2017, on the last Sunday of October, there was fall backward.
d8> new Date(Date.UTC(2017, 9, 28,12)).toLocaleString("en", {timeZone: "Africa/Casablanca"})
"10/28/2017, 1:00:00 PM"
d8> new Date(Date.UTC(2017, 9, 29,12)).toLocaleString("en", {timeZone: "Africa/Casablanca"})
"10/29/2017, 12:00:00 PM"

In 2018, there is no transition on the last Sunday of October.
d8> new Date(Date.UTC(2018,9,27,12)).toLocaleString("en", {timeZone: "Africa/Casablanca"})
"10/27/2018, 1:00:00 PM"
d8>  new Date(Date.UTC(2018,9,28,12)).toLocaleString("en", {timeZone: "Africa/Casablanca"})
"10/28/2018, 1:00:00 PM"


Bug: 473288
Test: See the above
Change-Id: Icc2c2a377e3c2d03c7d57cd99a1594773cb10c81
Reviewed-on: https://chromium-review.googlesource.com/c/1341453
Reviewed-by: Jungshik Shin <jshin@chromium.org>
10 files changed